Perhaps you should try some spelling variations:
dan thanh » dang thanh, danh thanh, ban thanh
nham thuc » nhan thuc, nam thuc, nham thu
thuc dan » thuc hanh, hoc dan, thuc vat
so sach » so sanh, bo sach, co sach
ve nham » ve nha, ve cham
vai cua » dai cua, hai cua, lai cua
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
tu nano » truc nano
tu nang » tru nang, tu nong, tu lang
vi cua » di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ((tu nang) or (tu nano)) mai hoi. hieu ve nham thuc dan thanh ((vi cua) OR (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((tu nang) OR (tu nano)) mai hoi. hieu ve nham thuc dan thanh ((vi cua) OR (vai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((tu nang) or (tu nano)) mai hoi. hieu ve nham thuc dan thanh ((vi cua) OR (vai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach ((tu nang) or (tu nano)) mai hoi. hieu ve nham thuc dan thanh ((vi cua) OR (vai cua)) tre*.